IGCSE Computer Science
11 videosRevision videos for IGCSE Computer Science, unit by unit: Grade 9 data representation, data transmission and hardware.
Grade 9 · Unit 3: Hardware
1:21Inside the CPU
The control unit, ALU and registers, the Von Neumann architecture and the three buses.
1:36The fetch-decode-execute cycle
Follow one instruction through the PC, MAR, MDR, CIR and ACC registers, then run a small program.
1:28What makes a CPU faster?
Clock speed, number of cores and cache size, with the run times worked out.
1:00Embedded systems
A computer built into a device for one job: examples, and how it differs from a general-purpose computer.
1:45Input devices
Keyboards, mice, touch screens, microphones, cameras, scanners and barcode / QR readers.
1:41Output devices
Screens, projectors, printers, 3D printers and speakers: what each one does.
1:06Sensors and actuators
A control loop: a sensor measures, the processor decides, an actuator acts. A thermostat shown step by step.
1:29Primary storage: RAM, ROM and virtual memory
Volatile RAM, non-volatile ROM with the boot program, and what virtual memory does when RAM is full.
1:30Secondary storage
Magnetic, optical and solid-state storage, plus cloud storage.
1:34Network hardware: NIC, MAC, IP and routers
What a network interface card, MAC address, IP address (IPv4 and IPv6) and router each do.
5:10Unit 3 quiz
Ten questions with a think-time countdown and explained answers.